Patterned fine particle film structures

ABSTRACT

A patterned fine particle film structure includes a fine particle layer including fine particles arranged and bound to a surface of a substrate coated with a patterned film including a first film compound having a first functional group. The fine particles are coated with films including a first coupling agent having a first coupling reactive group that undergoes a coupling reaction with the first functional group to form a bond. The fine particle layer is bound by a bond formed through a coupling reaction. In an embodiment, fine particles coated with films of a film compound that reacts with the first coupling reactive group and the fine particles are alternately bound to the substrate.

TECHNICAL FIELD

Embodiments described herein relate to patterned films of fineparticles.

BACKGROUND

The Langmuir-Blodgett (LB) technique using amphiphilic organic moleculesis conventionally known, in which the molecules are arranged over awater surface to deposit a monomolecular film on a surface of asubstrate. Also known is chemical adsorption (CA), in which amonomolecular film is deposited by chemical adsorption in a solutioncontaining a surfactant.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1(A) is an illustrative diagram schematically showing the sectionalstructure of a patterned single-layer fine particle film according to afirst embodiment.

FIG. 1(B) is an illustrative diagram schematically showing the sectionalstructure of a patterned multilayer fine particle film according to thesame embodiment.

FIG. 2(A) is an illustrative diagram schematically showing the sectionalstructure of a patterned single-layer fine particle film according to asecond embodiment.

FIG. 2(B) is an illustrative diagram schematically showing the sectionalstructure of a patterned multilayer fine particle film according to thesame embodiment.

FIGS. 3(A) and 3(B) are a set of conceptual diagrams, enlarged to themolecular level, illustrating a step of producing an epoxidized glasssubstrate in methods for producing the patterned fine particle films:

FIG. 3(A) shows the sectional structure of an unreacted glass substrate;and

FIG. 3(B) shows the sectional structure of a glass substrate on which amonomolecular film of a film compound having an epoxy group is formed.

FIG. 4(A) is a conceptual diagram, enlarged to the molecular level,illustrating a step of performing patterning treatment in the methodsfor producing the patterned fine particle films;

FIG. 4(B) is a conceptual diagram, enlarged to the molecular level,illustrating a step of performing patterning treatment according to anembodiment.

FIGS. 5(A) and 5(B) are a set of conceptual diagrams, enlarged to themolecular level, illustrating a step of producing epoxidized fine nickelparticles in the methods for producing the patterned fine particlefilms:

FIG. 5(A) shows the sectional structure of an unreacted fine nickelparticle; and

FIG. 5(B) shows the sectional structure of a fine nickel particle onwhich a monomolecular film of a film compound having an epoxy group isformed.

DETAILED DESCRIPTION

Referring to FIGS. 1(A) and 1(B), a patterned single-layer fine particlefilm 1 and a patterned multilayer fine particle film 3 according to thefirst embodiment will be described. The patterned single-layer fineparticle film 1 and the patterned multilayer fine particle film 3 eachincludes a fine particle layer in which epoxidized fine nickel particles(an example of first coated fine particles) 34 are arranged and bound toa surface of a reactive glass substrate (an example of a reactivesubstrate) 41.

In the patterned multilayer fine particle film 3, as shown in FIG. 1(B),the first to nth fine particle layers (where n is an integer of two ormore; n=2 in this embodiment) are sequentially stacked in order from thereactive glass substrate 41 side to the air interface side.

The surface of the reactive glass substrate 41 is coated with amonomolecular film 13 (see FIG. 3(B)) of a film compound having an epoxygroup (an example of a first film compound) and is further coated with afilm of 2-methylimidazole (an example of a first coupling agent) boundby a bond formed through a coupling reaction between an amino group (anexample of a first coupling reactive group) of 2-methylimidazole and theepoxy group.

The surfaces of reactive fine nickel particles 42 forming a second fineparticle layer are further coated with films of 2-methylimidazole (anexample of a third coupling agent) bound by a bond formed through acoupling reaction between an amino group (an example of a third couplingreactive group) of 2-methylimidazole and an epoxy group.

The reactive glass substrate 41 and the epoxidized fine nickel particles34 forming the first fine particle layer are bound to each other by abond formed through a coupling reaction between the epoxy group and theamino or imino group of 2-methylimidazole. Similarly, the epoxidizedfine nickel particles 34 forming the first fine particle layer and thereactive fine nickel particles 42 forming the second fine particle layerare bound to each other.

As shown in FIG. 1(B), the reactive fine nickel particles 42 can also bebound to the sides of the epoxidized fine nickel particles 34 of thefirst layer. It is noted that FIG. 1(B) is drawn with the size of thefine particles exaggerated relative to that of the actual pattern forillustration purposes.

Referring to FIGS. 3(A), 3(B), 4(A), 5(A), and 5(B), methods forproducing the patterned single-layer fine particle film 1 and thepatterned multilayer fine particle film 3 according to variousembodiments are disclosed. The method includes a step A (see FIG. 3) ofpreparing an epoxidized glass substrate 14 (an example of a coatedsubstrate) by bringing a solution containing an alkoxysilane compoundhaving an epoxy group (an example of a first film compound) into contactwith a surface of a glass substrate (an example of a substrate) 11 toform a bond between alkoxysilyl groups (an example of a first bindinggroup) and hydroxyl groups 12 on the surface of the glass substrate 11.The method further includes a step B (see FIG. 4) of preparing apatterned epoxidized glass substrate 22 or 24 through patterningtreatment in which the surface of the epoxidized glass substrate 14 issubjected to light irradiation (an example of energy irradiation)through a mask 21 covering a pattern region so that the epoxy group isleft only in the pattern region. The method also includes a step C (seeFIG. 5) of preparing the epoxidized fine nickel particles 34 by bringingan alkoxysilane compound having an epoxy group (an example of a secondfilm compound) into contact with the surfaces of fine nickel particles(an example of fine particles) 31 to form a bond between alkoxysilylgroups (an example of a second binding group) and hydroxyl groups 31 onthe surfaces of the fine nickel particles 31. The method additionallyincludes a step D of preparing the reactive glass substrate 41 (seeFIGS. 1(A) and 1(B)) by bringing 2-methylimidazole into contact with thesurface of the patterned epoxidized glass substrate 22 (see FIG. 4) tofacilitate a coupling reaction between the epoxy group and an aminogroup, and then binding the epoxidized fine nickel particles 34 to thesurface of the reactive glass substrate 41 by bringing the epoxidizedfine nickel particles 34 into contact with the surface of the reactiveglass substrate 41 to form a bond through a coupling reaction betweenthe epoxy group and an imino group (an example of a second couplingreactive group), followed by removing unbound epoxidized fine nickelparticles 34.

In step E the epoxidized fine nickel particles (an example of secondcoated fine particles) 34 are prepared by bringing a solution containingan epoxidized alkoxysilane compound (an example of a third filmcompound) into contact with the surfaces of the fine nickel particles 31to form a bond between alkoxysilyl groups (an example of a third bindinggroup) and hydroxyl groups 32 on the surfaces of the fine nickelparticles 31, and then preparing the reactive fine nickel particles (anexample of second reactive fine particles) 42 by bringing2-methylimidazole (an example of a second coupling agent) into contactwith the surfaces of the epoxidized fine nickel particles 34 so thatthey have films including 2-methylimidazole bound to the surfacesthereof by a bond formed through a coupling reaction between the epoxygroup (an example of a third functional group) and an amino group. In astep F the reactive fine nickel particles 42 are bound to the fineparticle layer of the epoxidized fine nickel particles 34 by bringingthe reactive fine nickel particles 42 into contact with the surface ofthe patterned single-layer fine particle film 1 or the patternedmultilayer fine particle film 3, which includes the fine particle layerof the epoxidized fine nickel particles 34, to form a bond through acoupling reaction between the epoxy group and the imino group, followedby removing unbound reactive fine nickel particles 42. In step G theepoxidized fine nickel particles 34 are bound to the fine particle layerof the reactive fine nickel particles 42 by bringing the epoxidized finenickel particles 34 into contact with the surface of the patternedmultilayer fine particle film 3, which includes the fine particle layerof the reactive fine nickel particles 42, to form a bond through acoupling reaction between the epoxy group and the imino group, followedby removing unbound epoxidized fine nickel particles 34.

he steps A to G will now be described in more detail below. Referring toFIGS. 3(A) and 3(B), in the step A, a film compound having an epoxygroup is brought into contact with the glass substrate 11 to produce theepoxidized glass substrate 14, with its surface coated with themonomolecular film 13 of the film compound having an epoxy group. Thesize of the glass substrate 11 is not particularly limited.

Any compound that can be adsorbed or bound to the surface of the glasssubstrate 11 to form a self-assembled monomolecular film may be used asthe film compound having an epoxy group. One example is an alkoxysilanecompound having a functional group including an epoxy group (oxiranering) at one terminal of a linear alkylene group and an alkoxysilylgroup (an example of a first binding group) at the other terminal, asrepresented by the following general formula (Chemical Formula 1).

In the above formula, the functional group E denotes the functionalgroup including an epoxy group, m denotes an integer of 3 to 20, and Rdenotes an alkyl group having one to four carbon atoms.

Specific examples of the film compound, having an epoxy group, that canbe used include the alkoxysilane compounds shown in Items (1) to (12)below.

-   (1) (CH₂OCH)CH₂O(CH₂)₃Si(OCH₃)₃-   (2) (CH₂OCH)CH₂O(CH₂)₇Si(OCH₃)₃-   (3) (CH₂OCH)CH₂O(CH₂)₁₁Si(OCH₃)₃-   (4) (CH₂CHOCH(CH₂)₂)CH(CH₂)₂Si(OCH₃)₃-   (5) (CH₂CHOCH(CH₂)₂)CH(CH₂)₄Si(OCH₃)₃-   (6) (CH₂CHOCH(CH₂)₂)CH(CH₂)₆Si(OCH₃)₃-   (7) (CH₂OCH)CH₂O(CH₂)₃Si(OC₂H₅)₃-   (8) (CH₂OCH)CH₂O(CH₂)₇Si(OC₂H₅)₃-   (9) (CH₂OCH)CH₂O(CH₂)₁₁Si(OC₂H₅)₃-   (10) (CH₂CHOCH(CH₂)₂)CH(CH₂)₂Si(OC₂H₅)₃-   (11) (CH₂CHOCH(CH₂)₂)CH(CH₂)₄Si(OC₂H₅)₃-   (12) (CH₂CHOCH(CH₂)₂)CH(CH₂)₆Si(OC₂H₅)₃

Herein the (CH₂OCH)CH₂O— group denotes the functional group (glycidylgroup) represented by Chemical Formula 2, and the (CH₂CHOCH(CH₂)₂)CH—group denotes the functional group (3,4-epoxycyclohexyl group)represented by Chemical Formula 3.

The epoxidized glass substrate 14 is produced by applying to the surfaceof the glass substrate 11 a reaction solution containing an alkoxysilanecompound having an epoxy group and an alkoxysilyl group (an example of asecond binding group), a condensation catalyst for promoting acondensation reaction between alkoxysilyl groups and the hydroxyl groups12 on the surface of the glass substrate 11, and a nonaqueous organicsolvent, and reacting them in air at room temperature. The applicationof the reaction solution may be performed by any method, such asdoctor-blade coating, dip coating, spin coating, spraying, or screenprinting.

The condensation catalyst used may be a metal salt, such as a metalcarboxylate salt, a metal carboxylate ester salt, a metal carboxylatesalt polymer, a metal carboxylate salt chelate, a titanate ester, or atitanate ester chelate.

The amount of condensation catalyst added may be 0.2% to 5% by mass,more specifically 0.5% to 1% by mass, of the amount of alkoxysilanecompound.

Specific examples of metal carboxylate salts include stannous acetate,dibutyltin dilaurate, dibutyltin dioctoate, dibutyltin diacetate,dioctyltin dilaurate, dioctyltin dioctoate, dioctyltin diacetate,stannous dioctanoate, lead naphthenate, cobalt naphthenate, and iron2-ethylhexanoate.

Specific examples of metal carboxylate ester salts include dioctyltinbisoctylthioglycolate ester salt and dioctyltin maleate ester salt.

Specific examples of metal carboxylate salt polymers include dibutyltinmaleate salt polymer and dimethyltin mercaptopropionate salt polymer.

Specific examples of metal carboxylate salt chelates include dibutyltinbisacetylacetate and dioctyltin bisacetyllaurate.

Specific examples of titanate esters include tetrabutyl titanate andtetranonyl titanate.

Specific examples of titanate ester chelates includebis(acetylacetonyl)di-propyltitanate.

The alkoxysilyl groups undergo a condensation reaction with the hydroxylgroups 12 on the surface of the glass substrate 11 to form themonomolecular film 13 of the film compound having an epoxy group, whichhas the structure represented by Chemical Formula 4 below. The threesingle bonds extending from the oxygen atoms bind to the surface of theglass substrate 11 or to the adjacent silicon (Si) atoms of the silanecompound, at least one of the bonds binding to a silicon atom on thesurface of the glass substrate 11.

The reaction may be facilitated in air at a relative humidity of 45% orless because the alkoxysilyl groups decompose in the presence of water.In addition, since the condensation reaction is inhibited by oil andwater on the surface of the glass substrate 11, such impurities arepreferably removed in advance by sufficiently cleaning and drying theglass substrate 11.

If the condensation catalyst used is one of the above metal salts, ittakes about two hours to complete the condensation reaction.

If one or more compounds selected from the group consisting of ketiminecompounds, organic acids, aldimine compounds, enamine compounds,oxazolidine compounds, and aminoalkylalkoxysilane compounds are used asthe condensation catalyst instead of the above metal salts, the reactiontime can be reduced to about ½ to ⅔.

Alternatively, if these compounds are used as a cocatalyst and mixedwith the above metal salts (they can be used in a mass ratio of 1:9 to9:1, although about 1:1 is preferred), the reaction time can be furtherreduced.

If, for example, the epoxidized fine nickel particles 21 are producedusing H3, a ketimine compound manufactured by Japan Epoxy Resins Co.,Ltd., as the condensation catalyst instead of dibutyltin oxide, with theother conditions being identical, the reaction time can be reduced toabout one hour without impairing the quality of the epoxidized finenickel particles 21.

In addition, if the epoxidized fine nickel particles 21 are producedusing a mixture of H3 from Japan Epoxy Resins Co., Ltd. and dibutyltinbisacetylacetonate (in a mixing ratio of 1:1) as the condensationcatalyst, with the other conditions being identical, the reaction timecan be reduced to about 20 minutes.

Examples of ketimine compounds that can be used include, but not limitedto, 2,5,8-triaza-1,8-nonadiene,3,11-dimethyl-4,7,10-triaza-3,10-tridecadiene,2,10-dimethyl-3,6,9-triaza-2,9-undecadiene,2,4,12,14-tetramethyl-5,8,11-triaza-4,11-pentadecadiene,2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene, and2,4,20,22-tetramethyl-5,12,19-triaza-4,19-trieicosadiene.

Examples of organic acids that can be used include, but not limited to,formic acid, acetic acid, propionic acid, butyric acid, and malonicacid.

The reaction solution can be produced using an organochlorine solvent, ahydrocarbon solvent, a fluorocarbon solvent, a silicone solvent, or amixed solvent thereof. To prevent hydrolysis of the alkoxysilanecompound, water is preferably removed from the solvent used with adesiccant or by distillation. In addition, the boiling point of thesolvent may be 50° C. to 250° C.

Specific examples of solvents that can be used include nonaqueoussolvents such as petroleum naphtha, solvent naphtha, petroleum ether,petroleum benzin, isoparaffin, normal paraffin, decalin, industrialgasoline, nonane, decane, kerosene, dimethyl silicone, phenyl silicone,alkyl-modified silicone, polyether silicone, and dimethylformamide.

In addition, alcohol solvents such as methanol, ethanol, and propanol ormixtures thereof can be used.

In addition, examples of fluorocarbon solvents that can be used includechlorofluorocarbon solvents, Fluorinert (manufactured by 3M Company ofthe United States), and Aflude (manufactured by Asahi Glass Co., Ltd.).These solvents may be used alone or in combination of two or more ifthey are sufficiently miscible with each other. In addition, anorganochlorine solvent such as dichloromethane or chloroform may beadded.

The concentration of the alkoxysilane compound in the reaction solutionmay be 0.5% to 3% by mass.

After the reaction, the glass substrate 11 is cleaned with a solvent toremove excess alkoxysilane compound and condensation catalyst remainingunreacted on the surface thereof, so that the epoxidized glass substrate14 is obtained, with its surface coated with the monomolecular film 13of the film compound having an epoxy group. FIG. 3(B) shows a schematicdiagram of the sectional structure of the epoxidized glass substrate 14thus produced.

The cleaning solvent used may be any solvent that can dissolve thealkoxysilane compound. For example, dichloromethane, chloroform, andN-methylpyrrolidone are cleaning solvents that are inexpensive, arehighly capable of dissolving the alkoxysilane compound, and can readilybe removed by air drying.

If the resultant epoxidized glass substrate 14 is left in air withoutbeing cleaned with a solvent after the reaction, some of thealkoxysilane compound remaining on the surface thereof is hydrolyzed bywater in air to form silanol groups, which undergo a condensationreaction with the alkoxysilyl groups. As a result, an ultrathin polymerfilm of polysiloxane is formed on the surface of the epoxidized glasssubstrate 14. Although not necessarily being covalently bound to thesurface of the epoxidized glass substrate 14, the polymer film, havingepoxy groups, displays the same reactivity as the monomolecular film 13of the film compound having an epoxy group for the epoxidized glasssubstrate 14. Even without cleaning, therefore, no problem arises in thestep C and the subsequent production process.

While an alkoxysilane compound having an epoxy group is used in thisembodiment, an alkoxysilane compound having an amino group at oneterminal of a linear alkylene group and an alkoxysilyl group at theother terminal may also be used, as represented by the following generalformula (Chemical Formula 5).

A compound having glycidyl groups at either terminal thereof can be usedas a coupling agent that reacts with an amino or imino group.

In the above formula, m denotes an integer of 3 to 20, and R denotes analkyl group having one to four carbon atoms. Specific examples of thefilm compound, having an amino group, that can be used include thealkoxysilane compounds shown in Items (21) to (28) below.

-   (21) H₂N(CH₂)₃Si(OCH₃)₃-   (22) H₂N(CH₂)₅Si(OCH₃)₃-   (23) H₂N(CH₂)₇Si(OCH₃)₃-   (24) H₂N(CH₂)₉Si(OCH₃)₃-   (25) H₂N(CH₂)₅Si(OC₂H₅)₃-   (26) H₂N(CH₂)₅Si(OC₂H₅)₃-   (27) H₂N(CH₂)₇Si(OC₂H₅)₃-   (28) H₂N(CH₂)₉Si(OC₂H₅)₃

In this case, however, among condensation catalysts that can be used forthe reaction solution, compounds containing tin (Sn) salts cannot beused as the condensation catalyst for an alkoxysilane compound having anamino group because they react with an amino group to form aprecipitate.

If an alkoxysilane compound having an amino group is used, the samecompounds, excluding tin carboxylate salts, tin carboxylate ester salts,tin carboxylate salt polymers, and tin carboxylate salt chelates, asused for an alkoxysilane compound having an epoxy group can be used asthe condensation catalyst alone or as a mixture of two or more.

The type and combination of cocatalyst that can be used, the type ofsolvent, the concentrations of the alkoxysilane compound, thecondensation catalyst, and the cocatalyst, the reaction conditions, andthe reaction time are similar to those for an alkoxysilane compoundhaving an epoxy group, and a description thereof will therefore beomitted.

While a glass substrate is used as the substrate in this embodiment, anoptical device such as a lens or a diffraction grating may also be usedas the substrate.

An alkoxysilane compound may also be used as the film compound if thesubstrate has active hydrogen groups, such as hydroxyl groups or aminogroups, on its surface. Specific examples of such a substrate includemetal foil and metal plates such as copper plates, aluminum plates, andsilicon wafers. Accordingly, a member including such a substrate as acomponent may also be used as the substrate, as exemplified byelectronic components such as semiconductor wafers and printed boardsand various mechanical components such as micromachines.

While the film compound used in this embodiment is a silane compoundthat undergoes a condensation reaction with the active hydrogen groupson the surface of the substrate, the film compound used may also be, forexample, a thiol or triazinethiol derivative, which forms a strong bondwith a gold atom, if a substrate having a gold plating layer is used, asin the step A.

While the film compound used in this embodiment is a silane compoundthat undergoes a condensation reaction with the active hydrogen groupson the surfaces of the fine particles, the film compound used may alsobe, for example, a thiol or triazinethiol derivative, which forms astrong bond with a gold atom, if fine gold particles or a substratehaving a gold plating layer is used.

Referring to FIG. 4(A), in the step B, the patterning treatment isperformed by exposing the surface of the epoxidized glass substrate 14through the mask 21 covering the pattern region to prepare the patternedepoxidized glass substrate 22, with the epoxy group selectively leftonly in the pattern region.

The mask used for the exposure may be formed of any material that is nottransparent or damaged by irradiation light at least during theexposure. For example, the mask may be made from a material used forreticles employed in photolithography in the production of, for example,semiconductor devices. The exposure may be full-size exposure or may bereduced projection exposure if, for example, a fine pattern is formed.

The light source used may be laser light from, for example, an excimerlaser such as a XeF (353 nm) laser, a XeCl (308 nm) laser, a KrF (248nm) laser, or an ArF (193 nm) laser. Referring to FIG. 4(A), irradiationwith laser light raises the temperature in an irradiated region, therebyremoving the film compound having an epoxy group that covers theirradiated region (23), so that the patterned epoxidized glass substrate22 is obtained (see FIG. 4(B)).

To prevent heat transfer to the region other than the irradiated region,the epoxidized film compound is preferably removed by pulse laserablation using a pulse laser.

The intensity of the laser light may be 0.1 to 0.3 J·cm⁻². If theintensity of the laser light falls below 0.1 J·cm⁻², the film compoundhaving an epoxy group cannot be sufficiently removed, and if theintensity exceeds 0.3 J·cm⁻², the glass portion of the epoxidized glasssubstrate 14 is removed.

If the intensity of the laser light falls within the above range, thepulse width may be 5 to 50 ns.

While the epoxidized film compound is removed by pulse laser ablation inthe above embodiment, another type of energy irradiation, such aselectron beam irradiation or X-ray irradiation, may be employed. Inaddition, instead of exposure through a mask, the epoxidized filmcompound may be removed from the region other than the pattern byselectively drawing the pattern directly on the epoxidized glasssubstrate 14 with, for example, an electron beam.

Referring to FIG. 4(B), in a step of performing patterning treatmentaccording to an embodiment, the patterned epoxidized glass substrate 24is prepared by applying a photopolymerization initiator to the surfaceof the epoxidized glass substrate 14 and exposing the surface of theepoxidized glass substrate 14 through the mask 21 covering the patternregion to facilitate a ring-opening polymerization of the epoxy group inthe exposed region so that the epoxy group is left only in the patternregion.

The photopolymerization initiator that can be used may be, for example,a cationic photopolymerization initiator such as a diaryliodonium salt.The light source used may be, for example, a high-pressure mercury lampor a xenon lamp.

In the step C, a film compound having an epoxy group similar to thatused in the step A is brought into contact with the fine nickelparticles 31 to produce the epoxidized fine nickel particles 34, withtheir surfaces coated with monomolecular films 33 of the film compoundhaving an epoxy group (see FIG. 5).

The size of the fine nickel particles 31 may be, but is not limited to,10 nm to 0.1 mm. If the size of the fine nickel particles 31 falls below10 nm, the effect of the molecular size of the film compound is nolonger negligible. If the particle size exceeds 0.1 mm, the mass of thefine nickel particles 31 is so large relative to their surface area thatthey cannot be supported after a coupling reaction.

The epoxidized fine nickel particles 34 are produced by dispersing thefine nickel particles 31 in a reaction solution containing analkoxysilane compound having an epoxy group, a condensation catalyst forpromoting a condensation reaction between alkoxysilyl groups and thehydroxyl groups 32 on the surfaces of the fine nickel particles 31, anda nonaqueous organic solvent, and reacting them in air at roomtemperature.

The type of alkoxysilane compound, having an epoxy group, that can beused in the step C, the types and combination of condensation catalystand cocatalyst, the type of solvent, the concentrations of thealkoxysilane compound, the condensation catalyst, and the cocatalyst,the reaction conditions, and the reaction time are similar to those ofthe step A, and a description thereof will therefore be omitted.

After the reaction, the fine nickel particles 31 are cleaned with asolvent to remove excess alkoxysilane compound and condensation catalystremaining unreacted on the surfaces thereof so that the epoxidized finenickel particles 34 are obtained, with their surfaces coated with themonomolecular films 33 of the film compound having an epoxy group. FIG.5(B) shows a schematic diagram of the sectional structure of theepoxidized fine nickel particles 34 thus produced.

The cleaning solvent used may be the same cleaning solvent as used inthe step A.

If the resultant epoxidized fine nickel particles 34 are left in airwithout being cleaned with a solvent after the reaction, some of thealkoxysilane compound remaining on the surfaces thereof is hydrolyzed bywater in air to form silanol groups, which undergo a condensationreaction with the alkoxysilyl groups. As a result, ultrathin polymerfilms of polysiloxane are formed on the surfaces of the epoxidized finenickel particles 34. Although not being covalently bound to the surfacesof the epoxidized fine nickel particles 34, the polymer films, havingepoxy groups, display the same reactivity as the monomolecular films 33of the film compound having an epoxy group for the epoxidized finenickel particles 34. Even without cleaning, therefore, no problem arisesin the step D and the subsequent production process.

While an alkoxysilane compound having an epoxy group is used in thisembodiment, an alkoxysilane compound having an amino group at oneterminal of a linear alkylene group and an alkoxysilyl group at theother terminal may also be used, as in the step A.

In addition, while the alkoxysilane compound used in this embodiment isthe same as that used in the step A, a different alkoxysilane compoundmay also be used. In that case, the alkoxysilane compound must have afunctional group that reacts and forms a bond with a coupling reactivegroup of the coupling agent used in the step D.

While fine nickel particles are used as the fine particles in thisembodiment, other inorganic fine particles, organic fine particles, ororganic-inorganic hybrid fine particles may be used. In an alternativeembodiment, organic and inorganic fine particles may be alternatelystacked.

The term “inorganic fine particles” encompasses conductive fineparticles, semiconductor fine particles, insulating fine particles,magnetic fine particles, fluorescent fine particles, light-absorbingfine particles, light-transmitting fine particles, and fine pigmentparticles. The term “organic fine particles” encompasses organicfluorescent fine particles, organic light-absorbing fine particles,organic light-transmitting fine particles, organic pigment fineparticles, and fine drag particles.

In addition, the term “organic-inorganic hybrid fine particles”encompasses fine drag particles for drug delivery systems (DDS), fineparticles for cosmetics, and organic-inorganic hybrid pigment fineparticles.

An alkoxysilane compound may also be used as the film compound for fineparticles other than fine nickel particles if they have active hydrogengroups, such as hydroxyl groups or amino groups, on their surfaces.Specific examples of such fine particles include metal oxides, such asalumina and lead oxide.

While the first and second film compounds used in this embodiment arefilm compounds having an epoxy group, they may be the same compound ordifferent compounds. In addition, the first and second film compoundsmay have different functional groups. For example, one of the first orsecond films has an epoxy group while the other of the first or secondfilms has an isocyanate group.

In the step D, the reactive glass substrate 41 (see FIGS. 1(A) and 1(B))is prepared by bringing 2-methylimidazole into contact with the surfaceof the epoxidized glass substrate 14 (see FIG. 3(B)) to facilitate acoupling reaction between the epoxy group and an amino group, and thenthe epoxidized fine nickel particles 34 are bound to the surface of thereactive glass substrate 41 by bringing the epoxidized fine nickelparticles 34 into contact with the surface of the reactive glasssubstrate 42 to form a bond through a coupling reaction between theepoxy group and an imino group, followed by removing unbound epoxidizedfine nickel particles 24.

Bonds are formed between 2-methylimidazole, which has amino and iminogroups at its 1- and 3-positions, respectively, and epoxy groups, withwhich they react, through the cross-linking reaction represented byChemical Formula 6 below.

The reactive glass substrate 42 is produced by applying a reactionsolution containing 2-methylimidazole and a solvent to the surface ofthe epoxidized glass substrate 14 and reacting them by heating. Theapplication of the reaction solution may be performed by any method,such as doctor-blade coating, dip coating, spin coating, spraying, orscreen printing.

The film precursor can be produced using any solvent in which2-methylimidazole is soluble. For example, based on price, volatility atroom temperature, and toxicity, lower alcohol solvents such as isopropylalcohol and ethanol are preferred.

The amount of 2-methylimidazole added, the concentration of the solutionapplied, the reaction temperature, and the reaction time areappropriately adjusted depending on, for example, the types of substrateand fine particles used and the thickness of the fine particle film tobe formed.

After the reaction, the epoxidized glass substrate 14 is cleaned with asolvent to remove excess 2-methylimidazole remaining unreacted on thesurface thereof so that the reactive glass substrate 41 is obtained(FIG. 3).

A dispersion of the epoxidized fine nickel particles 34 is applied tothe surface of the reactive glass substrate 41 thus prepared and isheated to bind the epoxidized fine nickel particles 34 to the surface ofthe reactive glass substrate 41 through a coupling reaction between theepoxy groups on the epoxidized fine nickel particles 34 and the iminogroups, derived from 2-methylimidazole, on the reactive glass substrate41, thus producing a patterned single-layer fine particle film 1 (seeFIG. 1) having a single fine particle layer.

In an embodiment, the heating temperature may be 100° C. to 200° C. Ifthe heating temperature falls below 100° C., it takes an extended periodof time for the coupling reaction to proceed. If the heating temperatureexceeds 200° C., the monomolecular films 13 (see FIG. 3) having epoxygroups and the reactive monomolecular film 31 (see FIG. 5(A)) mayundergo a decomposition reaction, thus making it impossible to obtain auniform patterned single-layer fine particle film 1.

After the reaction, excess epoxidized fine nickel particles 34 areremoved by cleaning with a solvent such as water or an alcohol.

While 2-methylimidazole is used as the coupling agent in thisembodiment, any imidazole derivative represented by Chemical Formula 7below may be used.

Specific examples of imidazole derivatives represented by ChemicalFormula 7 include those shown in Items (31) to (38) below.

-   (31) 2-methylimidazole (R₂=Me, R₄=R₅=H)-   (32) 2-undecylimidazole (R₂=C₁₁H₂₃, R₄=R₅=H)-   (33) 2-pentadecylimidazole (R₂=C₁₅H₃₁, R₄=R₅=H)-   (34) 2-methyl-4-ethylimidazole (R₂=Me, R₄=Et, R₅=H)-   (35) 2-phenylimidazole (R₂=Ph, R₄=R₅=H)-   (36) 2-phenyl-4-ethylimidazole (R₂=Ph, R₄=Et, R₅=H)-   (37) 2-phenyl-4-methyl-5-hydroxymethylimidazole (R₂=Ph, R₄=Me,    R₅=CH₂OH)-   (38) 2-phenyl-4,5-bis(hydroxymethyl)imidazole (R₂=Ph, R₄=R₅=CH₂OH)    where Me, Et, and Ph denote methyl, ethyl, and phenyl groups,    respectively.

The coupling agent used may also be a compound used as a curing agentfor epoxy resin, for example, an acid anhydride such as phthalicanhydride or maleic anhydride, dicyandiamide, or a phenol derivativesuch as novolac. In this case, an imidazole derivative may be used as acatalyst to facilitate the coupling reaction.

In this embodiment, the case where a film compound having an epoxy groupas a functional group is used is described. However, if a film compoundhaving an amino or imino group as a functional group is used, a couplingagent having two or three or more epoxy groups or two or three or moreisocyanate groups as coupling reactive groups is used. Specific examplesof compounds having isocyanate groups includehexamethylene-1,6-diisocyanate, toluene-2,6-diisocyanate, andtoluene-2,4-diisocyanate.

As in the case of 2-methylimidazole, the amount of diisocyanate compoundadded may be 5% to 15% by weight of the amount of epoxidized fine nickelparticles. In this embodiment, the solvent that can be used to producethe film precursor is exemplified by an aromatic organic solvent such asxylene.

If a film compound having an imino or amino group is used, additionally,the cross-linking agent used may be a compound having two or three ormore epoxy groups, for example, ethylene glycol diglycidyl ether.

In the step E, the epoxidized fine nickel particles 34 are prepared bybringing a solution containing an epoxidized alkoxysilane compound intocontact with the surfaces of the fine nickel particles 31 to form a bondbetween alkoxysilyl groups and the hydroxyl groups 32 on the surfaces ofthe fine nickel particles 31, and then the reactive fine nickelparticles 42 are prepared by bringing 2-methylimidazole into contactwith the surfaces of the epoxidized fine nickel particles 34 so thatthey have films formed of 2-methylimidazole bound to the surfacesthereof by a bond formed through a coupling reaction between the epoxygroup and the amino group derived from 2-methylimidazole.

The concentration of the 2-methylimidazole solution used, the reactionconditions, and so on are similar to those used in the preparation ofthe reactive glass substrate 41 in the step D except that, instead ofapplying the solution, the epoxidized fine nickel particles 34 aredispersed in the solution and heated. Therefore, a detailed descriptionof the reactive fine nickel particles 42 will be omitted in the interestof brevity.

Other coupling agents that can be used are similar to those in thepreparation of the reactive glass substrate 41 in the step D.

While the third film compound used in this embodiment is a film compoundhaving an epoxy group, it may be the same compound as or differentcompounds from one or both of the first and second film compounds. Inaddition, the third film compound may have a functional group differentfrom those of the first and second film compounds (for example, an aminogroup).

In the step F, the reactive fine nickel particles 42 are bound to thefine particle layer of the epoxidized fine nickel particles 34 bybringing the reactive fine nickel particles 42 into contact with thesurface of the patterned single-layer fine particle film 1 or thepatterned multilayer fine particle film 3, which includes the fineparticle layer of the epoxidized fine nickel particles 24, to form abond through a coupling reaction between the epoxy group and the iminogroup, followed by removing unbound reactive fine nickel particles 42.

In the step G, additionally, the epoxidized fine nickel particles 34 arebound to the fine particle layer of the reactive fine nickel particles42 by bringing the epoxidized fine nickel particles 34 into contact withthe surface of the patterned multilayer fine particle film 3, whichincludes the fine particle layer of the reactive fine nickel particles42, to form a bond through a coupling reaction between the epoxy groupand the imino group, followed by removing unbound epoxidized fine nickelparticles 34.

The reaction conditions of the steps F and G are similar to those of thestep E. Therefore, a detailed description of the reaction conditions forthe steps F and G will be omitted in the interest of brevity.

While the preparation of a fine particle film including two fineparticle layers has been described in this embodiment, a step H may befurther carried out in which the steps F and G are repeated in thatorder to form a fine particle film including n fine particle layers(where n is an integer of two or more). The step H may be terminatedeither in the step F or in the step G.

Referring to FIG. 2, a patterned single-layer fine particle film 2 and apatterned multilayer fine particle film 4 according to anotherembodiment will be described.

The patterned single-layer fine particle film 2 and the patternedmultilayer fine particle film 4 include a fine particle layer in whichthe reactive fine nickel particles 42 are arranged and bound to thesurface of the epoxidized glass substrate 14. In the patternedmultilayer fine particle film 4, as shown in FIG. 2(B), the first to nthfine particle layers (where n is an integer of two or more; n=2 in thisembodiment) are sequentially stacked in order from the epoxidized glasssubstrate 14 side to the air interface side.

The surface of the epoxidized glass substrate 14 is coated with themonomolecular film 13 of the film compound having an epoxy group.

The surfaces of the reactive fine nickel particles 42 forming the firstfine particle layer are further coated with films of 2-methylimidazolebound by a bond formed through a coupling reaction between an aminogroup of 2-methylimidazole and an epoxy group.

The epoxidized glass substrate 14 and the reactive fine nickel particles42 forming the first fine particle layer are bound to each other by abond formed through a coupling reaction between the epoxy group and theamino or imino group of 2-methylimidazole; similarly, the reactive finenickel particles 42 forming the odd-numbered fine particle layers andthe epoxidized fine nickel particles 34 forming the even-numbered fineparticle layers are bound to each other.

As shown in FIG. 2(B), the epoxidized fine nickel particles 34 can alsobe bound to the sides of the reactive fine nickel particles 42 of theodd-numbered layers, although FIG. 2(B) is drawn with the size of thefine particles exaggerated relative to that of the actual pattern forillustration purposes; they do not impair the shape of the pattern.

Referring to FIGS. 3(A), 3(B), FIGS. 4(A), 5(A), and 5(B), a method forproducing the patterned single-layer fine particle film 2 and thepatterned multilayer fine particle film 4 shown in FIGS. 2(A) and 2(B)includes a step A of preparing the epoxidized glass substrate 14 bybringing a solution containing an alkoxysilane compound having an epoxygroup into contact with a surface of the glass substrate 11 to form abond between alkoxysilyl groups and the hydroxyl groups 12 on thesurface of the glass substrate 11. The method further includes a step Bof preparing the patterned epoxidized glass substrate 22 (FIGS. 4(A) and4(B)) through patterning treatment by selectively irradiating thesurface of the epoxidized glass substrate 14 with light through the mask21 covering the pattern region so that the epoxy group is selectivelyleft only in the pattern region. The method also includes a step C ofpreparing the epoxidized fine nickel particles 34 by bringing analkoxysilane compound having an epoxy group into contact with thesurfaces of the fine nickel particles 31 to form a bond betweenalkoxysilyl groups and the hydroxyl groups 32 on the surfaces of thefine nickel particles 31 FIG. 5(A)). The method additionally includes astep D of preparing the reactive fine nickel particles 42 (FIGS. 2(A)and 2(B)) by bringing 2-methylimidazole into contact with the surfacesof the epoxidized fine nickel particles 34 to facilitate a couplingreaction between the epoxy group and an amino group, and then bindingthe reactive fine nickel particles 42 to the surface of the epoxidizedglass substrate 14 by bringing the reactive fine nickel particles 42into contact with the surface of the epoxidized glass substrate 14 toform a bond through a coupling reaction between the epoxy group and animino group (an example of a second coupling reactive group), followedby removing unbound reactive fine nickel particles 42.

The method further includes a step E of preparing the epoxidized finenickel particles 34 by bringing a solution containing an epoxidizedalkoxysilane compound into contact with the surfaces of the fine nickelparticles 31 to form a bond between alkoxysilyl groups and the hydroxylgroups 32 on the surfaces of the fine nickel particles 31. The methodalso includes a step F of binding the epoxidized fine nickel particles34 to the fine particle layer of the reactive fine nickel particles 42by bringing the epoxidized fine nickel particles 34 into contact withthe surface of the patterned single-layer fine particle film 2 or thepatterned multilayer fine particle film 4, which includes the fineparticle layer of the reactive fine nickel particles 42, to form a bondthrough a coupling reaction between the epoxy group and the imino group,followed by removing unbound epoxidized fine nickel particles 34. Themethod additionally includes a step G of binding the reactive finenickel particles 42 to the fine particle layer of the epoxidized finenickel particles 34 by bringing the reactive fine nickel particles 42into contact with the surface of the patterned multilayer fine particlefilm 4, which includes the fine particle layer of the epoxidized finenickel particles 34, to form a bond through a coupling reaction betweenthe epoxy group and the imino group, followed by removing unboundreactive fine nickel particles 42.

The preparation of the epoxidized glass substrate 14, the epoxidizedfine nickel particles 34, the reactive glass substrate 41, and thereactive fine nickel particles 42 and the reactions thereof in the stepsA to G are similar to those for the patterned single-layer fine particlefilm structure 1 and the patterned multilayer fine particle filmstructure 3 according to the various embodiments described with respectto FIGS. 1(A) and 1(B) and, therefore, a detailed description thereofwill be omitted.

Example 1 Preparation of Epoxidized Glass Substrate

A glass substrate was prepared, cleaned, and sufficiently dried.

A reaction solution was prepared by weighing out 0.99 part by weight of3-glycidoxypropyltrimethoxysilane (Chemical Formula 8, manufactured byShin-Etsu Chemical Co., Ltd.) and 0.01 part by weight of dibutyltinbisacetylacetonate (condensation catalyst) and dissolving them in 100parts by weight of hexamethyldisiloxane solvent. By this method, anepoxidized glass substrate could be prepared.

The reaction solution thus prepared was applied to the glass substrateand was left in air (relative humidity: 45%) to facilitate a reactionfor about two hours.

Afterwards, the glass substrate was cleaned with chloroform to removeexcess alkoxysilane compound and dibutyltin bisacetylacetonate.

Example 2 Preparation of Patterned Epoxidized Glass Substrate

The epoxidized glass substrate prepared in Example 1 was subjected tolaser ablation by irradiation with a KrF excimer laser (wavelength: 248nm; pulse width: 10 ns; laser intensity: 0.15 J/cm²) through a mask (0.5μm line-and-space) covering the pattern region to be formed to remove amonomolecular film, having epoxy groups, that covered the region otherthan the pattern region. By this method, a patterned epoxidized glasssubstrate was prepared.

A patterned epoxidized glass substrate could also be prepared byapplying the cationic photopolymerization initiator Irgacure (registeredtrademark) 250 (a mixture of(4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate)and propylene carbonate in a ratio of 3:1, manufactured by CibaSpecialty Chemicals plc) to the surface of the epoxidized glasssubstrate using MEK as a diluent and then irradiating it withfar-ultraviolet rays through a mask similar to the above mask tofacilitate a ring-opening polymerization of the epoxy groups of themonomolecular film that covered the region other than the patternregion.

Example 3 Preparation of Epoxidized Fine Nickel Particles

Anhydrous fine nickel particles with an average particle size of 30 nmwere prepared and sufficiently dried.

A reaction solution was prepared by weighing out 0.99 part by weight of3-glycidoxypropyltrimethoxysilane (Chemical Formula 8) and 0.01 part byweight of dibutyltin bisacetylacetonate (condensation catalyst) anddissolving them in 100 parts by weight of hexamethyldisiloxane solvent.

The reaction solution thus prepared was mixed with the fine nickelparticles and was stirred in air (relative humidity: 45%) to facilitatea reaction for about two hours.

Afterwards, the fine nickel particles were cleaned with trichlene toremove excess alkoxysilane compound and dibutyltin bisacetylacetonate.

Example 4 Preparation of Patterned Reactive Glass Substrate

An ethanol solution of 2-methylimidazole was applied to the surface ofthe patterned epoxidized glass substrate prepared in Example 2 and washeated at 100° C. to facilitate a reaction between the epoxy group andthe amino group of 2-methylimidazole, so that a patterned reactive glasssubstrate was obtained. Afterwards, the patterned reactive glasssubstrate could be cleaned with ethanol to remove excess2-methylimidazole.

Example 5 Preparation of Reactive Fine Nickel Particles

The epoxidized fine nickel particles prepared in Example 3 weredispersed in an ethanol solution of 2-methylimidazole and were heated at100° C. to facilitate a reaction between the epoxy group and the aminogroup of 2-methylimidazole so that reactive fine nickel particles wereobtained. The reactive fine nickel particles could be cleaned withethanol to remove excess 2-methylimidazole.

Example 6 Preparation of Patterned Fine Nickel Particle Film (1)

An ethanol dispersion of the epoxidized fine nickel particles preparedin Example 3 was applied to the surface of the reactive glass substrateprepared in Example 4 and was heated at 100° C. After the reaction, thereactive glass substrate was cleaned with water to remove excessepoxidized fine nickel particles.

An ethanol dispersion of the reactive fine nickel particles prepared inExample 5 was further applied to the surface of the patterned fineparticle film thus prepared, which included a single fine particlelayer, and was heated at 100° C. After the reaction, the patterned fineparticle film was cleaned with water to remove excess reactive finenickel particles so that a patterned fine particle film including twofine particle layers was obtained.

Example 7 Preparation of Patterned Fine Nickel Particle Film (2)

An ethanol dispersion of the reactive fine nickel particles prepared inExample 5 was applied to the surface of the patterned epoxidized glasssubstrate prepared in Example 2 and was heated at 100° C. After thereaction, the patterned epoxidized glass substrate was cleaned withwater to remove excess reactive fine nickel particles.

An ethanol dispersion of the epoxidized fine nickel particles preparedin Example 3 was further applied to the surface of the patterned fineparticle film thus prepared, which included a single fine particlelayer, and was heated at 100° C. After the reaction, the patterned fineparticle film was cleaned with water to remove excess epoxidized finenickel particles so that a patterned fine particle film including twofine particle layers was obtained.

Example 8 Preparation of Patterned Fine Nickel Particle Film (3)

The same processes as in Examples 1 and 3 were performed using areaction solution prepared by weighing out 0.99 part by weight of3-aminopropyltrimethoxysilane (Chemical Formula 9, manufactured byShin-Etsu Chemical Co., Ltd.) and 0.01 part by weight of acetic acid(condensation catalyst) and dissolving them in 100 parts by weight ofhexamethyldisiloxane-dimethylformamide mixed solvent (1:1 v/v) toprepare an aminated glass substrate and aminated fine nickel particleswith a particle size of about 100 nm.

The aminated glass substrate was subjected to the same process as inExample 2 to prepare a patterned aminated glass substrate.

In addition, the same processes as in Examples 4 and 5 were performedusing p-phenylene diisocyanate as a coupling agent to prepare a reactiveglass substrate and reactive fine nickel particles having an isocyanategroup as a coupling reactive group.

These materials were used to perform the same processes as in Examples 6and 7, so that patterned fine particle films including one fine nickelparticle layer (thickness: 100 nm) or two fine nickel particle layers(thickness: 200 nm) were obtained.

The invention claimed is:
 1. A film structure, comprising: a substrate;a first alkoxysilane linker linked to the substrate through a firstactive hydrogen group of the substrate, the first alkoxysilane linkerhaving a first epoxide reactant product; a fine particle; a secondalkoxysilane linker linked to the particle through a second activehydrogen group of the particle, the second alkoxysilane linker having asecond epoxide reactant product; and a coupling agent including animidazole group linking the first alkoxysilane linker and the secondalkoxysilane linker so as to link the particle to the substrate throughthe two alkoxysilane linkers and the coupling agent including theimidazole group disposed therebetween.
 2. The film structure of claim 1,comprising a plurality of fine particles linked to the substrate to forma particle layer arranged into a pattern.
 3. The film structure of claim2, wherein the particle film includes a single particle layer.
 4. Thefilm structure of claim 1, further comprising: a second fine particlehaving one or more third active hydrogen groups; a third alkoxysilanelinker linked to the second particle through the third active hydrogengroup, said third alkoxysilane linker having a third epoxide reactantproduct; and a second coupling agent linking the second epoxide reactantproduct of the second alkoxysilane to the third epoxide reactant productof the third alkoxysilane thereby linking the second fine particle tothe fine particle.
 5. The film structure of claim 1, wherein thesubstrate includes a glass, lens, diffraction grating, metal, foil,aluminum, copper, silicon, semiconductor, electronic printed boards,passivation film, a capacitor, or combinations thereof.
 6. The filmstructure of claim 1, wherein the one or more first and second activehydrogen groups include hydroxyl groups or amino groups.
 7. The filmstructure of claim 1, wherein one or more of the alkoxysilane linkersinclude the epoxy reactant product formed from reacting an epoxy groupwith the coupling agent, and the coupling agent comprises2-methylimidazole.
 8. The film structure of claim 7, wherein a resultingstructure linking the fine particle to the substrate includes the firstalkoxysilane linker linked to the substrate, which is linked to the2-methylimidazole reactant product, which is linked to the secondalkoxysilane linker, which is linked to the particle so that theresulting linking structure includes two epoxy groups with the2-methylimidazole reactant product disposed therebetween.
 9. The filmstructure of claim 1, wherein the fine particles include at least oneof: inorganic fine particles including a metal; inorganic fine particlesincluding a metal oxide; organic fine particles including a polymer;organic fine particles including a polymer micelle; or organic-inorganichybrid fine particles.
 10. The film structure of claim 1, wherein theparticle includes nickel.